The objective of this application is to assess the impact of newer approaches to dietary modification with the intent of reducing the risk of developing cardiovascular disease. The specific aims of the application are as follow: 1) to assess the impact of substituting two classes of fats specifically formulated to substitute for hydrogenated fats (i.e., trans-free margarines and genetically modified/selectively bred oils) on serum lipid levels (total, VLDL, LDL, HDL, HDL2 and HDL3 cholesterol; triglyceride; apo A-l and B; Lp[a]), immune function, and prostaglandin levels, and 2) to address unresolved issues related to plant sterols, including the relative efficacy of currently available preparations, impact of the fat and cholesterol content of the diet, and effect of dosing frequency on serum lipids, endogenous cholesterol synthesis, cholesterol absorption, and fat soluble vitamin levels. Study subjects will be older (50-75 y) hypercholesterolemic female and male subjects (LDL cholesterol 130-160 mg/dl). Each 5-week diet phase will be scheduled in randomized order; all food and drink will be provided. In Part 1, Study 1, subjects will consume each of 3 diets (30 percent fat [2/3 experimental fat], 80 mg cholesterol/1000 kcal) with the following experimental fats: conventional soft margarine; trans-free margarine (interesterified palm kernel + liquid oil); trans-free margarine (fully hydrogenated soybean oil + liquid oil). In Part 1, Study 2, subjects will consume each of 6 diets (as above) with the following experimental fats: hydrogenated soybean (shortening), high oleic sunflower, high oleic soybean, high oleic canola, low saturated soybean and low linolenic soybean oils. In Part 2, Study 1, subjects will consume each of 4 diets (38 percent fat [15 percent SFA, 14 percent MUFA, 6 percent PUFA], 200 mg cholesterol/1000 kcal), baseline and the following: sitostanol ester; sitostenol ester, and genetically modified high sterol oil. In Part 2, Study 2, subjects will consume each of 4 plant sterol enriched diets, high fat (as above) with high (200 mg) or low (80 mg) cholesterol/1000 kcal, and low fat (20 percent fat [5 percent SFA, 7.5 percent MUFA, 7.5 percent PUFA]) with high or low cholesterol. In Part 2, Study 3, the effect of dosing regime will be assessed using the most efficacious plant sterol as identified in Study 1 and diet as in Study 2 (single bolus or in 3 divided doses). There is a rapid introduction of foods designed to optimize blood lipid levels into the marketplace. Limited data are available on efficacy, especially within current U.S. dietary patterns. Virtually no information is available on the effect of altering the fatty acid profile of the diet on biological parameters other than serum lipids. The investigators state that data derived from the proposed studies could contribute to the database on which to formulate more specific public health recommendations regarding the variables described.